This invention relates to a fuel injection pump for internal combustion engines, especially multi-cylinder serial pumps which include pump pistons driven by cam shaft via cam means. The present invention relates, more particularly, to such pumps having a chamber within its housing, the chamber having the shape of an elongated recess and having an opening. A single cover is provided over the opening, and a sealing means is positioned between the housing and the cover, the sealing means including an O-ring which is tightened between an offset on the circumference of the cover on a seat defined by a receiving bore. The receiving bore is provided at a transition between the chamber and the outer surface of the housing.
Known fuel injection pumps of the above-described construction, wherein a single cover closes a downwardly opening chamber within the housing intended to receive a cam shaft, usually have an O-ring seal between the cover and the housing. The seat for the O-ring is formed in known manner, customary in a machine, by a 45.degree. beveling at the transition between the housing chamber and the bottom surface of the pump housing. Covers, or more precisely, bottom closing covers of the above-described kind require, for good sealing and for producing an appropriate compressing stress in the O-ring as well as for satisfactory contact with the bottom surface of the pump housing that both in their transverse as well as longitudinal extent, the edge of the housing extends beyond the housing itself and beyond the O-ring seat. The length of the cover directly affects the total construction length of the pump because the thickness of the frontal walls of the pump, which are longitudinally adjacent to the attachment region for the cover, is predetermined by the necessary constructional volume of the cam shaft bearing and by the wall thickness of frontal attachment flanges of the pump. The wall thickness is subject to conditions of rigidity and cannot fall below a minimum dimension. These conditions of constructional volume are especially critical if, in order to reduce the constructional height of the pump, the cover is mounted at the shortest possible distance from the cam shaft.